Used in immunosuppressive therapy, particularly to prevent organ transplant rejection. It targets the IL-2 receptor alpha chain (CD25) on activated T-cells, blocking interleukin-2 signaling and dampening the immune response. Commonly administered in kidney transplant patients in combination with other immunosuppressants like cyclosporine and corticosteroids. Its use reduces the incidence of acute rejection episodes during the early post-transplant period. Also employed in research settings as a reference antibody for flow cytometry, immunohistochemistry, and immunoassays involving CD25 expression.